Sample preparation system for iron and steel samples

ABSTRACT

In a sample preparation system for iron and steel samples, a grinding machine (1) with a stamping device (2) and/or a cutting machine (3), as well as transport devices (7 to 12), form a modular structural unit for the input, output and transfer of samples. In this case it is possible to connect the stamping device (2) having an integrated robot (20), a sandblasting unit (26), an inductive heating station (27), a sample crusher (25) and a plurality of stamping machines (28, 29, 30) for lollypop samples, and the cutting machine comprising a rotating clamping chuck (31) and an adjustable cutting grinding wheel (32) for cylindrical and conical samples, to a grinding machine (1), which forms the central module and contains a rough and a fine grinding device (18, 20), a cooling device (19) and a clamping device (14) for the samples, and which grinding machine (1) has a dust removal connector (13) for the central removal of dust. The clamping device (14) is embodied in block shape and has two clamping jaws which are movable in respect to each other in two stages.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a system by means of which iron and steelsamples are prepared for sample analysis.

For production control and quality assurance in the steel industry,samples are regularly taken in the course of processing and from thefinished products. The chemical composition of these samples isdetermined by means of optical emission, X-ray fluorescence andcombustion analyses.

It should be possible to prepare the samples fully automatically and ina reproducible manner in accordance with the requirements of theanalysis apparatus, which might comprise, for example, the generation ofa plane surface or the removal of small pieces by stamping.

2. Object of the Invention

It is the object of the invention to provide a sample preparation systemfor iron and steel samples, where the processing machines to be used forfully automatic and reproducible sample preparation are combined in avariable manner into a fully automatic unit, so that they permit theproduction of qualitatively perfect samples.

A further object of the invention is seen in the provision of a simplyconstructed and dependably operating clamping device for the samples,which, with short movement paths and small power expenditure, permits acompact construction with a large clamping range and a great clampingforce.

The sample preparation system in accordance with the invention iscomposed of a modular unit, where it is possible to selectively assign astamping device and/or a cutting machine to a grinding machine and wherethe two or three modules for the input and output of samples andtransfer of samples are connected by transport systems, which results inthe automatic movement of the samples into the preparation system andwithin the same.

The individual modules are equipped with processing stations, whichperform high-quality preparation of the samples.

The grinding machine is furthermore equipped with a compactly builtclamping device for the samples to be ground which, with short movementpaths and small expenditure of power, has a comparatively large clampingrange and great clamping force of its clamping jaws.

The device is simply constructed and operates in two clamping stages.The first clamping stage results in a movement of the clamping jawstowards each other by means of the axial twisting of a clamping disk,and the second clamping stage is attained by applying pressure to theclamping disk. In this way the clamping jaws are first preset to alarger range and subsequently adjusted to a considerably smaller range.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the invention is illustrated in the drawingsand will be described in detail below.

FIG. 1 is a schematic top view of a modular sample preparation systemcomprising a grinding machine, a stamping device and a cutting machine,

FIG. 2 is a schematic top view of the sample preparation system withsample input and output devices, as well as a sample transfer device anda clamping device,

FIG. 3 is a schematic top view of the sample preparation system withprocessing stations of the lower level of the stamping device,

FIG. 4 is a schematic top view of the sample preparation system withprocessing stations disposed in the upper level,

FIG. 5 is a schematic front view of the grinding machine withdisplaceable clamping device and rough and fine grinding device,

FIGS. 6 to 8 show various types of samples,

FIG. 9 is a vertical section through the clamping device in accordancewith line III--III of FIG. 12, which the clamping jaws in the openposition,

FIG. 10 is a vertical section through the clamping device in the firstclamping stage of the clamping jaws,

FIG. 11 is a vertical section through the clamping device in the secondclamping stage of the clamping jaws,

FIG. 12 is a horizontal section through the clamping device inaccordance with line I--I of FIG. 9,

FIG. 13 is a horizontal section through the clamping device inaccordance with line II--II of FIG. 9,

FIG. 14 is a lateral view of the clamping device in partial section.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The sample preparation systems consists of three modules, a grindingmachine (1), a stamping device (2) and a cutting machine (3).

The samples (4, 5, 6) are fed to the system via transport devices (7, 8,9, 10, 11, 12) and are transferred within the system from one module tothe next.

The sample transfer within the preparation system can also be performedby an integrated robot (12). Conveyor belts can be provided as transportdevices (7 to 11) for the input and output as well as the transfer ofthe samples (4 to 6).

The central module is represented by the grinding machine (1), to whichcan be connected, depending on the type of sample, the stamping device(2) module for lollypop samples (4) (also called lollypop samples) andthe cutting machine (3) module for cylindrical and conical samples (5,6).

Central dust removal of the system is accomplished by means of a dustremoval connector (13) of the grinding machine (1), because of which thesystem can be placed in the immediate vicinity of sensitive analysisapparatus.

The grinding machine (1) has a clamping device (14), which is moved inthe X direction by means of a support (15) on guides (16) via aservomotor drive (see FIG. 5).

The clamping device (14) is moved in the Y direction via a secondservomotor drive and the guide for this movement is inside the support(15).

The sample (4, 5, 6) is picked up by the clamping device (14) from asample support (17) and is clamped and pre-ground on a rough grindingdevice (18). Cooling of the sample (4, 5, 6) takes place subsequently inthe cooling device (19) by means of a fluid medium, for example, water.The fine grinding operation on a fine grinding device (20) follows.During this time the sample (4, 5, 6) is additionally cooled by means ofa gaseous medium, for example, compressed air. This sequence iscontrolled by a program. The sequence can be arbitrarily changed byprior settings and in this way adapted to the requirements of therespective sample type.

With samples subject to cracking, a program is selected which pre-coolsthe sample with compressed air and then cools it down to roomtemperature with water.

Grinding on the rough grinding device (18) is accomplished by moving thesample (4, 5, 6), which is firmly clamped in the clamping device (14),oscillatingly over a contact wheel (21), around which runs the grindingbelt (22). At the same time, this contact wheel (21) drives the grindingbelt (22). In the course of the oscillating movement a step-by-stepmovement in the Y direction is performed until the previously setgrinding depth has been reached. This grinding process takes placeswiftly (approximately 3 seconds for a usual grinding depth of 0.6 mm).The sample (4, 5, 6) is not in contact with its entire surface, but onlywith a narrow area of the radius of the contact wheel (21) and thus ofthe grinding belt (22). This fact prevents excessive heating of thesample (4, 5, 6). Too much heating can have the effect of creatingcracks in the surface of the sample or that micro-cracks, which may bepresent, gape open, so that water can enter in the course of liquidcooling, which has a disadvantageous effect during the subsequentanalysis.

It is also possible to use a cup grinding wheel instead of the grindingbelt (22) for the rough grinding device (18). This cup grinding wheel isfastened on a vertically extending grinding spindle.

This method is particularly suited for grinding of iron samples becauseof its long service life.

Grinding on the fine grinding device (20) takes place in that the sample(4, 5, 6), which is firmly clamped in the clamping device (14) isbrought above the fine grinding belt (23) and the feed takes place inthe Y direction.

In this case a grinding table (24) resiliently seated underneath thegrinding belt (23) generates the counter force required for grinding.

This grinding method generates the reproducible surface required foranalysis.

The short contact with the grinding belt (23) (approximately 2 seconds)does not cause noticeable heating of the sample (4, 5, 6) and reducesthe possibility of material transfer from the remainder of the sample tothe surface of the sample (4, 5, 6) to be analyzed.

This fact is of essential importance for unadulterated analysis.

The stamping device (2) has a central robot (12), which transfers thesamples (4, 5, 6) to the individual processing stations (25, 26, 27, 28,29, 30). These processing stations (25 to 30) are arranged in asemi-circle around the robot (12). The robot (12) can pick up thesamples (4, 5, 6) from the transport devices (8, 9, 10) and take themout of the system again via the same path.

Transfer of the samples (4, 5, 6) into the grinding machine (1) isaccomplished by the transport device (11), which takes the samples (4,5, 6) from the module 2 to the module 1 (FIG. 2).

On the lower level of the stamping device (2) are disposed processingstations in the form of a sandblasting unit (26), an inductive heatingstation (27) and a sample crusher (25), and on the upper lever threestamping machines (28 to 30).

The sandblasting unit (26) has two obliquely directed nozzles, whichfeed the blasting medium in a compressed air stream to the lollypopsample (4a) and remove the scales from it. By means of this, falsereadings in the combustion analysis are prevented to the greatestextent.

The lollypop sample (4) is inductively heated to 700° to 900° C. in theinductive heating station (27). Because of this it is possible to stampeven steel with a high carbon content and highly alloyed steel.

The robot (12) performs the introduction of the lollypop sample (4a).Overheating of the sample (4a) is prevented by a heat monitoring device.

Iron samples cannot be stamped. To obtain sample pieces for combustionanalysis, either the sample itself or a portion thereof is crushed, forwhich the sample crusher (25) has been provided. The sample pieces to bebroken off may be, for example, a cast lollypop (4a) or a sample stem(4b). A tool can be inserted into one of the stamping machines (28, 29or 30), which breaks off the lollypop (4a) or the stem (4b) from thesample (4). Breaking into small pieces then is performed by the built-insample crusher (25) into which the lollypop (4a) or the stem (4b) istransferred by the robot (12). The crushing operation is performedbetween two jaws of hard metal which move towards each other in acircular movement. The drive is hydraulically operated. The gap width ofthe crusher jaws is adjustable, so that the grain size of the crushedparts can be varied.

The lollypop (4a) is broken off from the sample (4) in the firststamping machine (28). This is necessary in case of lollypop samples (4)if the samples (4) are to be placed into the cassettes of the X-rayfluorescence spectrometer. Sample pieces (4c, 6a, 5a) of 0.5 to 1 g arerequired for the combustion analysis of carbon, nitrogen and sulfur. Forthis purpose small rounds (4c, 6a, 6b) are stamped out of the sampledisks. The rounds (4c, 6a, 6b) are transported by means of an injectorin a pipeline with a gaseous medium to a receptacle device, for example,a reservoir, or directly to the analysis device. The rounds (4c, 6a, 6b)are stamped out in the second stamping machine (29).

The third stamping machine (30) shears off the stem (4b), because thestem (4b) on the sample (4) would make further manipulation difficult.The sheared-off stem (4b) is caught in a collecting hopper.

The cutting machine (3) is used to cut sample disks (5b, 5c) out ofcylindrical and conical sample bodies (5, 6) for further processing inthe stamping device (2) and the grinding machine (1). The samples (5, 6)are automatically clamped into a rotating clamping chuck (31) and arethen cut through with a cutting grinding wheel (32) of the cuttingmachine (3). A plane surface is generated because of the rotation of thesample (5, 6) during the cutting process. Furthermore, rotation reducesheating of the sample (5, 6), because the cutting grinding wheel (32) isnot in contact any farther then the center of the sample (5, 6) and thecontact position changes constantly.

The straight cut of this cutting process also makes possible theproduction of thin sample disks (5b, 6b).

The cutting grinding wheel (32) is seated in an adjustment device (33)by means of which it is possible to even out the wear of the cuttinggrinding wheel.

The various samples for spectroscopy are shown in FIGS. 6 to 8.

The clamping device (14) in accordance with FIGS. 9 to 14, is in theshape of a block and has two clamping jaws which can be moved in respectto each other in two stages. In this case the two clamping jaws (34) areeach fastened on a clamping jaw support (35), with which they are guidedin their movements toward or away from each other in a guide (36)underneath the cube-shaped, multiple housing (37) of the clamping device(14).

A clamping disk (38) is seated axially rotatable in the housing (37) andis seated with its rotating shaft (39) in the upper housing area. Therotating shaft (39) is in axial rotational contact with a toothed wheel(41) via a groove-and tongue connector (40) and is provided axiallydisplaceable in a limited range in respect to this toothed wheel (41).

Two toothed racks (42) engage the toothed wheel (41) and are fastened topressure medium cylinders (43).

Two clamping grooves (44), extending eccentrically around the rotatingshaft (40) of the disk, are cut into the clamping disk (38), which areengaged by bolts (45), which are connected with the clamping jaws (34)fixed against movement and which cause the first clamping stage duringdisk torsion.

In this case the lower longitudinal ends of these bolts (45) have beeninserted into the clamping jaw supports (35) and are secured therein byscrews (46) or the like. The clamping grooves (44) are cut out of theclamping disk (38) so they extend obliquely, i.e. they extend in thedirection of the rotating shaft diverging from each other towards thebottom.

The bolts (45) frictionally engage the clamping grooves (44).

A pressure plate (47) is disposed on the top of the clamping disk (38),which on the one side covers the clamping grooves (44) and with itsother side results in a piston surface (47a) which can be put underpressure.

A pressure spring (48) is disposed coaxially with the rotating shaft(40) and is supported on one end on the clamping disk (38) and on theother on an abutment plate (49) disposed between the housing (37) andthe clamping jaw supports (35).

The housing (37) of the clamping device (14) is maintained movable inheight on the support (15) via vertical telescopic guides (50).

The opened position of the clamping jaws (34) is shown in FIG. 9. Asshown in FIG. 12, the toothed racks (42) are extended outwardly inopposite directions by the pressure medium cylinders (43).

FIG. 13 also shows the opened position of the clamping device (14), inwhich the clamping disk (38) has been twisted into the end position inwhich the two bolts (45) are located in the ends of the groove which arethe farthest from the rotating shaft (39).

The toothed wheel (41), and thus the rotating shaft (40), are turned inthe direction of the arrow "A" by the displacement towards each other ofthe two toothed racks (42) by means of the pressure medium cylinders(43), and the clamping disk (38) is also twisted in the direction of thearrow "A" by this. Because of this the two grooves (44) move around thebolts (45) and in the course of this pull the two bolts (45) towardseach other and in the direction of the rotating shaft (39), since thedistance of the grooves (44) from the rotating shaft (39) decreasesbecause of the eccentric path of the grooves.

By means of this the clamping jaw supports (35) and thus the clampingjaws (34) are moved towards each other into the first clamping positionin accordance with FIG. 10. In this twisted position of the clampingdisk, the other ends of the grooves (44), which are closer to therotating shaft (39), are located at a distance in front of the bolts(45), looking in the direction of rotation. The rotational angle of theclamping disk (38) is less than 90 degrees.

Subsequently the movement of the clamping jaws (34) into the secondclamping position takes place where, through a conduit (51) (pressuremedium conduit), a pressure medium is brought to bear on the pistonsurface (47a) of the pressure plate (47).

The piston surface (47a) is put under pressure and by means of thispressure the clamping disk (38) is downwardly displaced in an axialdirection by the amount (Z) in FIG. 10, while the rotating shaft (39)simultaneously can also be axially displaced in respect to the toothedwheel (41) because of the groove-and-tongue connector (40).

In this downward movement of the clamping disk (38), the conical surface(44a) of the clamping disks (44) acts on the bolts (45) and causesfurther pushing towards each other of the clamping jaws (34) until thebolts (45) ar stopped at the ends of the grooves.

This second clamping path is approximately 1 mm for each clamping jaw(34).

With a stroke of the clamping disk (38) cf approximately 10 mm, thestroke of the clamping jaws of 1 mm each is achieved by means of theconical surface (44a).

The piston surface (47a) is comparatively large and, with a pressure of4 bar, a clamping force of approximately 8,000 kp is achieved.

A comparatively large clamping path of the clamping jaws, which is up to30 mm, has been achieved by the axial twisting of the clamping disk (38)and the subsequent displacement of the clamping disk (38).

With decreasing pressure, the pressure spring (48) causes axial returnof the clamping disk (38) into the first clamping stage and subsequentlythe displacement of the toothed racks (42) causes a return of theclamping disk (38) and thus the opening of the clamping jaws (34).

We claim:
 1. A preparation system for iron and steel samples, saidpreparation system comprising: a grinding machine (1), a stamping device(2) and optionally depending on the type of said samples being analyzed,a cutting machine (3), as well as transport devices (7 to 12) for theinput, output and transfer between said grinding machine, stampingdevice and if optionally used said cutting machine of saidsamples;wherein housing means for containing each said grinding machine,said stamping device and, if optionally used, said cutting machineengaged together form a single modular structural unit; said grindingmachine having a clamping device (14) and grinding devices (18, 20) forsaid samples; wherein said clamping device (14) for said samples is inthe shape of a block and has two clamping jaws (34); said clampingdevice having means for moving said clamping jaws towards each other intwo stages.
 2. A preparation system in accordance with claim 1, whereinsaid clamping device (14) has a clamping disk (38), which is axiallyrotatable by a pressure medium cylinder (43), toothed racks (42) and atoothed wheel (41), with cut-out clamping grooves (44) extendingeccentrically around a rotating shaft (39) of said clamping disk;saidcut-out clamping grooves are engaged by bolts (45), which are fixedagainst movement to said clamping jaws (34) and which generate a firstclamping stage int he course of the twisting of said clamping disk (38);and said clamping disk (38) with said bolts (45) and said clamping jaws(34) being axially displaceable for a second clamping stage by means ofpressure form a pressure medium.
 3. A preparation system in accordancewith claim 1, wherein said two clamping jaws (34) are each fastened onone of two clamping jaw supports (35), together with which said twoclamping jaws (34) are movably guided towards and away from each otherin a guide (36) underneath a cube-shaped, multiple housing (37) of saidclamping device (14).
 4. A preparation system in accordance with claim2, wherein said clamping disk (38) is axially rotatable seated with saidrotating shaft (39) in an upper housing area; said clamping disk beingsecured against torsion and axially displaceable, with said rotatingshaft (39) through a tongue-and-groove connection (40) with said toothedwheel (41).
 5. A preparation system in accordance with claim 2, whereintwo pressure medium cylinders (43) are disposed in an upper area of saidhousing (37), each of which has a toothed rack (42) interacting withsaid toothed wheel (41) and which provides an axial twisting of saidclamping disk by an opposite movement of said toothed racks (42).
 6. Apreparation system in accordance with claim 2, wherein said two grooves(44) have been cut into said clamping disk (38) so that they obliquelydiverge downwardly and towards the outside, and that they limit, bymeans of their groove end farthest removed from said rotating shaft(39), the opening position of said clamping jaws (34) and, by means oftheir groove end located closest to said rotating shaft, the closingposition of clamping jaws (34).
 7. A preparation system in accordancewith claim 2, wherein said two bolts (45) have been inserted into saidtwo clamping jaw supports (35), with their lower longitudinal ends andare secured by means of screws (46) or the like, and that with theirupper longitudinal ends they engage said grooves (44) movably and in africtionally connected manner.
 8. A preparation system in accordancewith claim 2, wherein a pressure plate (47) is disposed on said clampingdisk (38), which covers said clamping grooves (44) and which, for thepurpose of an axial displacement of said clamping disk (38), can be putunder pressure by a pressure medium fed by a conduit (51) on an uppersurface, which forms a piston surface (47a).
 9. A preparation system inaccordance with claim 2, wherein a pressure spring (48) is disposedcoaxially with said rotating shaft (39) of said clamping disk, which onthe one end is supported on said clamping disk (38) and on the other endon an abutment plate (49), disposed between said housing (37) and saidtwo clamping jaw supports (35).
 10. A preparation system in accordancewith claim 2, wherein said clamping grooves (44) forming conical surface(44a) with their outer, obliquely extending groove surfaces, which acton said bolts (45).
 11. A preparation system in accordance with claim 1,wherein said clamping device (14) is maintained in a height-adjustablemanner via telescopic guides on a support (15) and is movable, togetherwith said support (15), on horizontal guides (16) above said grindingdevices (18, 20).
 12. A preparation system for iron and steel samples,said preparation system comprising:a first central module having ahousing enclosing therein said grinding machine (1) including a roughgrinding device, a fine grinding device (18, 20), at least one coolingdevice (19) and a clamping device (14) for said samples (4, 5, 6), saidfirst central module joined to a second module having a housingenclosing therein an integrated robot (12), a sandblasting unit (26), aninductive heating station (27), a sample crusher (25) and a plurality ofstamping machines (28, 29, 30) comprising a stamping device processinglollypop samples (4) as said samples for analysis, said housing of saidfirst central module joined to said housing of said second module andthereafter optionally joined to a housing of a third module forprocessing cylindrical and conical samples (5, 6) of said samples foranalysis; said housing of said third module enclosing a cutting stationhaving a cutting machine (3) consisting of a rotating clamping chuck(31) and an adjustable cutting grinding wheel (32) for said processingof cylindrical and conical samples (5, 6) of said samples for analysis:transport devices for the input, output and transport between said firstcentral module, said second module and if optionally joined, said thirdmodule of said samples; said housing of said first central module, saidhousing of said second module and said housing of said third module whenoptionally joined to said housing of said first central module and saidhousing of said second module forming a modular structural unit; andsaid grinding machine (1) having a central dust removal connector (13)to serve said modular structural unit.
 13. A preparation system inaccordance with claim 12, wherein said first module (1) is provided witha first transport device (7) for the input and output of said samples,said plurality of stamping machines is provided with a second transportdevice (8) for the input and output of said samples and said cuttingmachine is provided with a third transport device (9) for the input ofsamples, a fourth transport device (10) is provided between said cuttingmachine (3) and said plurality of stamping machines and a fifthtransport device is provided between said plurality of stamping machinesand said grinding machine (1), wherein all transport devices (7, 8, 9,10, 11) are constituted as conveyor belts.
 14. A preparation system inaccordance with claim 12, wherein said clamping device (14) for saidsamples (4, 5, 6) in said grinding machine (1) is movable in ahorizontal and a vertical direction.
 15. A preparation system inaccordance with claim 12, wherein said rough grinding device and saidfine grinding device (18, 20) have endless, rotating grinding belts (22,23), said rough grinding device (18) having means for oscillatinglymoving said samples (4, 5, 6) over a first of said rotating grindingbelts (22), driven by a contact wheel (21), and means for simultaneouslyfeeding said samples in steps to a grinding depth, and, while feeding tosaid grinding depth, being held in said fine grinding device (20)against a second of said grinding belts (23) and a grinding table (24),resiliently seated under said one of said grinding belts.
 16. Apreparation system in accordance with claim 12, wherein said roughgrinding device (18) has a cup grinding wheel fastened to a verticalgrinding spindle.
 17. A preparation system in accordance with claim 12,wherein said clamping device (14) for said samples is in the shape of ablock and has two clamping jaws (34);said clamping device having meansfor moving said clamping jaws towards each other in two stages.
 18. Apreparation system in accordance with claim 12, wherein said clampingdevice (14) has a clamping disk (38), which is axially rotatable via apressure medium cylinder (43), toothed racks (42) and a toothed wheel(41), with cut-out clamping grooves (44) extending eccentrically arounda rotating shaft (39) of said clamping disk;said cut-out clampinggrooves are engaged by bolts (45), which are fixed against movement tosaid clamping jaws (34) and which generate a first clamping stage in thecourse of the twisting of said clamping disk (38); and said clampingdisk (38) with said bolts (45) and a said clamping jaws (34) beingaxially displaceable for a second clamping stage by means of pressurefrom a pressure medium.
 19. A preparation system in accordance withclaim 17, wherein said two clamping jaws (34) are each fastened on oneof two clamping jaw supports (35), together with which said two clampingjaws (34) are movably guided towards and away from each other in a guide(36) underneath the cube-shaped, multiple housing (37) of said clampingdevice (14).
 20. A preparation system in accordance with claim 18,wherein said clamping disk (38) is axially rotatable seated with saidrotating shaft (39) in an upper housing area;said clamping disk beingconnected, secure against torsion and axially displaceable, with saidrotating shaft (39) through a tongue-and-groove connection (40) withsaid toothed wheel (41).
 21. A preparation system in accordance withclaim 18, wherein two pressure medium cylinders (43) are disposed in anupper area of said housing (37), each of which has a toothed rack (42)interacting with said toothed wheel (41) and which provides an axialtwisting of said clamping disk by an opposite movement of said toothedracks (42).
 22. A preparation system in accordance with claim 18,wherein said two grooves (44) have been cut into said clamping disk (38)so that they obliquely diverge downwardly and towards the outside, andthat they limit, by means of their groove end farthest removed from saidrotating shaft (39), the opening position of said clamping jaws (34)and, by means of their groove end located closest to said rotatingshaft, the closing position of clamping jaws (34).
 23. A preparationsystem in accordance with claim 18, wherein said two bolts (45) havebeen inserted into said two clamping jaw supports (35), with their lowerlongitudinal ends and are secured by means of screws (46) or the like,and that with their upper longitudinal ends they engage said grooves(44) movably and in a frictionally connected manner.
 24. A preparationsystem in accordance with claim 18, wherein a pressure plate (47) isdisposed on said clamping disk (38), which covers said clamping grooves(44) and which, for the purpose of an axial displacement of saidclamping disk, can be put under pressure by a pressure medium fed by aconduit (51) on an upper surface, which forms a piston surface (47a).25. A preparation system in accordance with claim 18, wherein a pressurespring (48) is disposed coaxially with said rotating shaft (39) of saidclamping disk, which on the one end is supported on said clamping disk(38) and on the other end on an abutment plate (49), disposed betweensaid housing (37) and said two clamping jaw supports (35).
 26. Apreparation system in accordance with claim 18, wherein said clampinggrooves (44) form a conical surface (44a) with their outer, obliquelyextending groove surfaces, which act on said bolts (45).
 27. Apreparation system in accordance with claim 12, wherein 27 said clampingdevice (14) is maintained in a height-adjustable manner via telescopicguides on a support (15) and is movable, together with said support(15), on horizontal guides (16) above said grinding devices (18, 20).